The present invention relates generally to yarn splicing devices of the type having a splicing chamber wherein two yarn ends may be spliced by means of vortices of compressed air admitted into the chamber through entrance openings.
Conventionally, the joinder of yarn ends in spinning or bobbin winding machines is performed almost exclusively by splicing procedures, commonly utilizing compressed air. Often, an individual splicing device may be provided at each spinning or winding position in such machines. Accordingly, a considerable increase in the performance of the individual spinning and winding positions is made possible since each correction of a yarn break and each connection of a new yarn to a preceding one is performed automatically at the particular spinning or winding position.
The preparation of the yarns as well as the splicing process itself is known to have a considerable influence on the strength of the resultant splice. The objective in each case is to obtain a splice of a strength at least approaching that of the yarn being spliced. The actual strength of any given splice depends upon whether the compressed air is directed into the splicing chamber in a manner producing an optimal vortexing of the fibers of the individual yarn ends, which is a function in each case of varying yarn parameters such as, for example, the yarn count, the constituent fiber material and the twist direction of the yarn. Thus, a splicing chamber must be specifically designed in relation to particular well-defined yarn parameters and splicing requirements.
As a result, it has become conventional practice in the use of known splicing devices to provide a number of interchangeable splicing heads, each of which is adapted for optimal splicing performance with yarns of specific characteristics. Accordingly, when the operating characteristics of a spinning or winding machine are altered, such as a change in the yarn material, yarn count or twist, new splicing heads must typically be substituted in the splicing devices at the individual spinning or winding positions. This requirement of exchanging the splicing heads disadvantageously requires a considerably amount of work and further requires that an expensive inventory of interchangeable splicing heads be maintained.
U.S. Pat. No. 4,397,140 discloses a known device and method for splicing multi-filament yarn or tow of differing diameters ranging from 100 to 2850 denier. To this end, several compressed air entrance openings are provided in the splicing device, each of which is individually connected to a respective compressed air supply line in which a respective regulator valve is provided to control the splicing air as needed during the splicing process. However, this device is only suitable for rather course yarns and tow, as indicated from the dimensions of the splicing chamber and the denier range of yarns and tow disclosed in this patent. Moreover, the provision of an individual connection of each compressed air entrance opening to an individual regulator valve represents a considerable expense, especially with regard to coordinating the opening actuation of the individual valves.